The invention relates to a control arrangement for a high-pressure cleaning system having a high-pressure pump and at least one spray gun which can be connected to the high-pressure pump by way of a high-pressure line.
In the case of high-pressure spraying or cleaning systems, as used, for example, for cleaning outside walls of boats or the like, the pressures of the liquid exiting from the spray guns are extremely high. This results in special safety requirements, also with respect to other high-pressure cleaning system, particularly concerning the switching-on/switching-off and/or regulating of the pressure.
Although mechanical solutions are largely safe with respect to operating errors, because of the high occurring pressures, a signal transmission in an electromagnetic manner is preferred between the spray gun and the high-pressure distributor. This signal transmission also requires special safety measures.
Thus, it is ruled out to guide the signal from the spray gun simply from a switch at the spray gun by a two-wire line from the spray gun to the high-pressure distributor or a control circuit assigned to the latter, because malfunctioning because of line damagexe2x80x94for example, on sharp edgesxe2x80x94cannot be excluded. For this reason, four-wire cables have been found to be successful for the signal transmission. The four-wire cables are equipped with relatively expensive connectors which can easily be damaged when not handled carefully.
In addition to the four-wire solution, radio controls exist which, however, are not always operable, for example, in the hull, which is full of corners.
The demand therefore exists for a reasonably priced and nevertheless safe control circuit for high-pressure cleaning systems. The creation of such a control circuit is the object of the invention.
The invention achieves this goal by a control arrangement for a high-pressure cleaning system having at least one gun circuit at the spraying device or spray gun and at least one analyzing circuit connected with the gun circuit and situated at a high-pressure distributor or at the high-pressure pump for determining the switching condition of an on/off switch on the spray gun. The at least one gun circuit is connected by a conductive connection at the high-pressure hose with the machine mass or ground, particularly the high-pressure pump, and has the on/off switch and at least one oscillator impresses a signal identifying the switching condition of the switch on the current flow to the analyzing circuit. A single-wire connection is provided between the at least one gun circuit and the at least one analyzing circuit, by means of which a supply voltage can be applied to the gun circuit.
The invention also achieves the additional partial objectxe2x80x94which can also be considered independentlyxe2x80x94of designing the control circuit such that a faulty connection of the spray guns, particularly an exchange of the spray guns at the high-pressure distributor or at the high-pressure pump, is easily detected.
The invention achieves this separate goal by the control arrangement comprising a monitoring circuit for protecting a high-pressure cleaning system with several spray guns, which can be connected to the high-pressure cleaning system by high-pressure lines, against faulty connections and/or exchanges of the spray guns at the connections assigned to them. The monitoring circuit has closed circuits from the analyzing circuits assigned to the connections by lines to respective gun circuits on the spray guns and by the high-pressure hoses or by electric connections directly assigned to the latter back to the machine mass. In addition, a coupling-in device, assigned to each CPU, impresses a respective identification signal on the current to the gun circuit at the spray guns by the single-wire line, and a sensor, preferably a current detector, is assigned to each connection for sensing the variation of the current signal.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.